Diagnose A/C Compressor Clutch Control Systems; Determine Necessary Action
Diagnose A/C compressor clutch control systems; determine necessary action.
Lesson Plan for
AUT 188-189/AUT 293
Automotive Service Technology Section D/Automotive Special Problems
Course HS Title: / Automobile Service Technology/Special Problems / Program:KCTCS Courses included in HS Title: (Lesson is prepared for course highlighted.)
KCTCS Course No. / KCTCS Course Title
Introduction/Context / This lesson will instruct the student on how to diagnose A/C compressor clutch control systems, and determine necessary action. Knowledge of these techniques and the skills required to correct problems associated with this task are necessary for a student to acquire if they wish to compete for high paying, high skilled jobs in an Automotive Repair Facility. Entry level technicians need to be able to perform this task to 100% accuracy. Incorrectly performing this task can lead to an automobile accident or create customer satisfaction issues.
Prepared By / School / Date:
Grade Level / No. Students / No.IEP's: / Lesson Length:
Task
Diagnose A/C compressor clutch control systems; determine necessary action.
No. / Objective
1 / Given the proper tools and instruction, the student will be able to diagnose A/C compressor clutch control systems, determine necessary action, and pass a written test covering the task with 100% accuracy.
Connections:
Skills Standards:OH 001
OH 002
OH 003
OD 002
OD 003
OD 005
Common Core Technical Standards:
TD-SYS-2
New Common Core Standards:
RST 11-12.2
RST 11-12 3
A-CED-4
N-Q-1
New Generation Science Standards:
HS-PS2-5.
HS-PS3-3.
HS-PS3-5.
INSTRUCTIONAL MATERIALS/TECHNOLOGY
Teacher Designed Materials and Other Handouts
Textbooks and Workbooks
Chris Johanson / Auto Heating and Air Conditioning / 2004 / Goodheart Wilcox / 284-287
Motor Information Systems / ASE Test Preparation Guide / 2009 / Prentice Hall/Pearson / 458-459
Web Addresses
Today's Class / Melior / www.todaysclass.com
Equipment
As Needed / Pulley Puller Set / Various
As Needed / Snap Ring Plier Set / Various.
Content/Presentation/Demonstration Outline
Inform students that once the driven plate has been removed, the drive plate and pulley assembly can be removed. Tell students that most pulley assemblies are held to the compressor nose by a large snap ring. Once the snap ring has been removed, the pulley and bearing assembly can be removed from the compressor. Let them know that some pulleys are pressed onto the compressor and must be removed with a puller. Also, the clutch bearing is usually attached to the pulley and will be removed with the pulley.
INSTRUCT STUDENTS ON ELECTROMAGNETIC REMOVAL: Inform students that if the electromagnet failed any tests, it can be replaced once the clutch pulley has been removed. Let them know that the electromagnet may be bolted to the front of the compressor, or may be held to the compressor nose by a snap ring. Tell students to remove the fasteners as necessary and remove the electromagnet.
Instruct students to inspect the electromagnet for overheated or shorted windings. Also tell them to check for contact with the electromagnet and the pulley. If the electromagnet shows evidence of damage, have them replace it. Let them know that some older systems deliver current to the electromagnet through brushes. Remind them to inspect the brushes for wear and replace if necessary.
INTSRUCT STUDENTS ON HOW TO DO A CLUTCH INSPECTION: Inform students that the mating faces on the clutch should be checked for wear and scoring. Explain that light wear and scoring are normal and under these circumstances, the clutch does not need replacement. Let them know that if the faces are heavily scored, worn, or damaged, they should be replaced.
Remind students to also check the pulley grooves for wear and damage. Inform students that if the driven plate uses vulcanized rubber to connect the inner and outer portions, be sure and check the rubber for signs of overheating. If the rubber section is melted or charred, tell them the plate should be replaced. Tell students to check metal connections for breakage or bending. If one plate is defective, both clutch plates should be replaced.
INSTRUCT STUDENTS ON HOW TO DO A CLUTCH BEARING INSPECTION: Explain that the clutch bearing can be inspected to ensure it is not damaged. Tell students to turn the bearing's inner race and note any roughness or binding. If the bearing does not turn smoothly, it should be replaced. Let students know that most bearings are held to the drive plate and pulley assembly with a snap ring. If needed, tell students to remove the snap ring and pull the old bearing from the pulley assembly. Inform them to check the snap ring to ensure it is not bent or damaged. Have them slide the new bearing into position and reinstall the snap ring. Let them know that some clutch bearings must be installed using a special tool.
INSTRUCT STUDENTS ON HOW TO DO AN ELECTROMAGNETIC AND CLUTCH REPLACEMENT: Be sure to tell students that before replacing the electromagnet and clutch assembly, they should make sure the mounting faces of the compressor are not damaged. Instruct students that to install the electromagnet, place it in position and install the fasteners. Tell them to be sure the electrical connectors are in the same position as originally. Let students know that if the electromagnet mounting uses alignment pins, be sure to install the mounting flange over the pins before tightening any fasteners. Explain that proper alignment is important to prevent contact between the electromagnet and pulley assembly. Tell them that once the electromagnet is installed, install the electrical connector.
Let students know that some drive and driven plates and pulley assemblies must be installed using special tools. Other assemblies can be slid into position or lightly hammered into place. Explain that once the pulley assembly is installed, tell students to make sure it turns freely without contacting the electromagnet. If there is any contact between parts, instruct them to remove the pulley and correct the problem.
Inform students that most compressor shafts have a key and keyway. The keyway slot in the driven plate must be aligned with the key before the plate is installed. Let them know that many driven plates can be installed by tightening the retaining nut into place, but that others require special installation tools.
Applications/Practice
Evaluation and feedback Prior to Testing or Lab Work
STUDENT ASSESSMENT:(Assess student progress with performance criteria.)
IMPACT--Reflection/Analysis of Teaching and Learning: (How did students’ progress in relation to the state objectives? Was the instruction successful? Analyze samples of student work particularly that which is unsatisfactory, for the purpose of planning further instruction.)
REFINEMENT--Lesson Extension and Follow-up: (To be filled in as the lesson is modified during initial planning and/or during the teaching learning process.)